Devices, such as handheld mobile communication devices, conventionally include input arrangements that provide some form of feedback to a user indicating that an action has been detected by the communication device. These are usually used in for example keystroke.
Three-dimensional sensing in a volume above the display of a device to detect gesture together with suitable user interface (UI) is supposed to become popular. The UI may be 3D as well and also be used together with a 3D display or a projector.
One method is to sense an object, e.g. a users hand, in a 3D volume is to use capacitive or electric field sensing. FIG. 1 illustrates a device 150 for capacitive and electric field sensing based on transmitting a signal 10 by means of one or several electrodes 151 and then receiving the response with another electrode(s) 152. The electrodes may be arranged behind a display layer 153 and controlled by a controller 154. If an object is close enough to the touch surface, a change in the capacitive coupling between the electrodes and the ground will be detected as the received signal strength will change.
One problem with the data input (text, drawing, and control) on small and/or medium sized touch sensitive screens, is the precision. Specially, for example in case of text input precision is necessary because of the narrow input elements (keys).